Hiya!
Like what the members above said IELTS can be quite a long journey, mind wrecking and also stressing (all of the TESTS are stressing anyway) but it doesnt mean that YOU REALLY NEED TO TAKE IELTS. There are other ENGLISH TESTS that you can take for your visa application which are more quicker (if you opt to) and easier. I passed IELTS like jlags and rayna but I wouldnt say that it didnt do my head in cos it did! LOL
For example TOEIC, it is another English Test and Hopkins is one of the registered test providers. It is more easier as you dont need to take writing and reading tests that IELTS have.
Regarding to reviews and materials, you can do self review and surf online or join workshops if youre not confident enough (will cost you money thought).
I used IDP Australia on taking the test as I was enroled in an IELTS Review Centre in Davao under IDP OZ. Since your in CDO, visit this link.
http://www.idp.com/ielts.aspx
Here is the UKBA link for registered english test providers.
http://www.ukba.homeoffice.gov.uk/si...lish-tests.pdf